Drafting system having a supporting roll for offset top feed roll

ABSTRACT

The axially aligned top roller pairs of adjacent drafting units of a spinning, twisting or roving machine are journaled on respective shafts, and that top roller pair which serves as the top feed roll of two adjacent drafting units is positioned in nipping relation to a corresponding bottom feed roll, but the top feed roller pair is offset rearwardly of the bottom feed roll. Therefore, in order to prevent the top feed roller pair from tilting excessively about the point at which the load is being applied to the shaft therefor, an idler supporting roll is positioned beneath and in nipping relation to the top feed roller pair and is rotatable by the top feed roller pair and the strands passing between the same and the idler roll.

Unite States Patent 1191 Staneff 1451 July 31, 1973 4] DRAFTING SYSTEMHAVING A SUPPORTING ROLL FOR OFFSET TOP FEED ROLL [75} Inventor: StefanStaneff, l-lerzongenaurach,

Germany [73] Assignee: lndustriewerk Schaetfler, OHG,

Herzongenaurach, Germany 22 Filed: Nov. 3, 1971 211 Appl. 190.; 195,160

Related US. Application Data [63] Continuation-in-part of Ser. No.153,615, June 16,

[52] US. Cl. l9/258, 19/293 [51] Int. Cl D0lh 5/70 [58] Field of Search19/236, 244, 246-261,

[56] References Cited UNlTED STATES PATENTS 3,537,145 11/1970 Meert etal. 19/258 FOREIGN PATENTS 0R APPLICATIONS 500,677 11/1954 Italy 19/261Primary Examiner-Dorsey Newton Attorney-Donald M. Seltzer [57] ABSTRACTThe axially aligned top roller pairs of adjacent drafting units of aspinning, twisting or roving machine are journaled on respective shafts,and that top roller pair which serves as the top feed roll of twoadjacent drafting units is positioned in nipping relation to acorresponding bottom feed roll, but the top feed roller pair is offsetrearwardly of the bottom feed roll. Therefore, in order to prevent thetop feed roller pair from tilting excessively about the point at whichthe load is being applied to the shaft therefor, an idler supportingroll is positioned beneath and in nipping relation to the top feedroller pair and is rotatable by the top feed roller pair and the strandspassing between the same and the idler roll.

5 Claims, 3 Drawing Figures PATENTED L 3 1 975 SEEN 2 BF DRAFTING SYSTEMHAVING A SUPPORTING ROLL FOR OFFSET TOP FEED ROLL This application is acontinuation-in-part of my copending application, Ser. No. 153,615,filed June 16, 1971 and entitled HIGH DRAFT TEXTILE DRAFT- ING SYSTEMAND METHOD.

The drafting system of said copending application includes a drivenbottom feed roll which is offset upwardly out of a plane passing throughthe axes of the other bottom drafting rolls by an amount about equal toone-half of its own diameter, and a top feed roll, in the form of a pairof axially spaced cots or rollers journaled on a roller neck shaft, isoffset rearwardly with respect to the bottom feed roll in such a mannerthat the textile strands, upon passing through the nips formed by thetop feed roller pair and the bottom feed roll, are looped about thebottom feed roll through an arc of about 90 to 110 as they pass throughthe respective breaker drafting zones in their course to the nextsucceeding set of top and bottom drafting rolls. The total length of thepath of each strand of textile fibers between the nips of the feed rollsand the next succeeding set of drafting rolls is greater than themaximum staple length of the fibers in the strands, and the uncontrolledlength of the path of each strand between the bottom feed roll and saidnext succeeding set of drafting rolls is less than the average staplelength of the fibers, thus providing a highly effective control of thefibers in the strands passing through the breaker drafting zones. Suchfiber control in the breaker drafting zones permits substantially higherbreak drafts and substantially higher total drafts than drafting systemswhich do not have such fiber control.

Since the top feed roller pair is rearwardly offset considerably withrespect to the bottom feed roll and the downward pressure or load isapplied to a relatively narrow medial portion of the roller neck shaftof the top feed roller pair, the top feed roller pair tends to tiltabout the medial portion of the roller neck shaft due to the differingtensile forces of the textile strands acting on the two cots or rollersthereof as caused by the normal differences in the tension in thestrands in the breaker drafting zones forwardly of the feed roll nipsand as by the parting of one or the other of the strands. Thus, the axisof the top feed roller pair may not extend parallel with the axis of thebottom feed roll. This problem is even more critical in relatively widegauge spinning, twisting or roving machines. For example, the gauge ordistance between the spindles of a spinning machine may be up to 100 to260 millimeters (about 3 /16 inches to 10 A inches), and the relativelynarrow control of the top feed roller pair by the top roll holders orcarriers of the usual loading arms engaging the medial portion of theroller neck shaft will not prevent, with certainty, the tilting of thetop feed roller pair if it is set back in the manner described withrespect to the bottom feed roll.

It is therefore an object of this invention to provide means forpreventing the two rollers or cots of the top feed roll from tiltingexcessively relative to the bottom feed roll when the top feed roll isoffset relative to the bottom feed roll in a direction parallel to thetravel of the textile strands between the feed rolls.

In the disclosed and preferred embodiment there is provided an adjacentpair of three-roller drafting units of the type disclosed in saidcopending application, but wherein an idler supporting roll ispositioned beneath and in nipping relation with the top feed roller pairfor the two adjacent drafting units, which idler supporting roll isrotated solely by the top feed roller pair and the strands passingtherebetween to the nips between each top feed roller and the bottomfeed roll. Thus, the idler supporting roll stabilizes the top feedroller pair relative to the bottom feed roll and substantiallyeliminates any tendency for the top feed roller pair to tilt relative tothe bottom feed roll regardless of whether the load or downward pressureis applied to the roller neck shaft of the top feed roller pair in adirection perpendicular to the mean plane of the paths of the strandsthrough the drafting units or in a direction inclined thereto. Byutilizing the idler supporting roll of this invention, the load on thetop feed roll can be effected at a right angle to the mean draftingplane so that practically any known form of weighting arms may be usedwith the drafting system.

Some of the objects of the invention having been stated, other objectsand advantages will appear as the description proceeds, when taken inconnection with the accompanying drawings, in which-- FIG. 1 is aschematic side elevation of one of a pair of drafting units embodyingthe invention and showing a top roll loading device in associationtherewith;

FIG. 2 is an enlarged view of the drafting unit shown in FIG. 1, butomitting the roll stand and the top roll loading device; and

FIG. 3 is a schematic plan view taken substantially along line 33 inFIG. 1, and showing both of the drafting units.

Referring more specifically to the drawings, the drafting system isembodied in a pair of side-by-side, three-roller, double apron draftingunits including three sets or pairs of top and bottom drafting rollscommon to both drafting units. The top and bottom rolls of the first setserve as feed rolls and are broadly designated at 11, 11a, the topand'the bottom rolls of the second pair serve as middle, intermediate orapronsupporting drafting rolls and are indicated at 12, 12a, and the topand bottom rolls of the third pair serve as delivery rolls and areindicated at 13, 13a.

Each top drafting roll includes a pair of axially spaced cots or rollersa, b journaled or rotatably mounted on opposing end portions of acorresponding roller neck shaft 0, and strands l4, 15 of textile staplefibers; e.g., rovings, pass from suitable sources through openings orpassages in respective laterally reciprocating guide members, trumpetsor condensers 16, 17 and beneath the respective rollers a, b of top feedroll 11. Each roller a, b of top feed roll 11 forms a nip 20 with acorresponding boss of bottom feed roll 1 1a, and each strand l4, 15extends upwardly through nip 20 and partially around the bottom feedroll 11a and into a respective breaker drafting zone A defined betweenthe nips 20 of feed rolls 11, 11a and the trips 21 formed byintermediate drafting rolls 12, 12a and by respective draft aprons 12b,12c looped thereover. The proximal reaches of aprons 12b, 12c of thedouble apron draft mechanism extend into a main or secondary draftingzone B defined between the intermediate nips 21 and front nips 22 formedby delivery rolls 13, 13a.

Although top feed roll 11 is slightly lower than the succeeding toprolls 12, 13, the axes of all of the top drafting rolls 1 1-13 aredisposed in a substantially common plane which is substantially parallelto the mean plane of the draft path of each of the strands l4, 15 oftextile fibers through the drafting unit. The intermediate and deliverybottom drafting rolls 12a, 13a also have their axes disposed in a planeextending substantially parallel with the plane through the axes of thetop drafting rolls l1l3. However, the axis of the bottom feed roll 1 lais offset upwardly, out of the plane passing through the axes of thebottom intermediate or apronsupporting roll 12a and the bottom deliveryroll 13a, by a distance equal to about one-half the diameter of bottomfeed roll 11a, so that the upper portion of bottom feed roll 11a isdisposed above the plane of the imaginary straight line extendingbetween the lowermost surfaces of the first and second top draftingrolls 11, 12. Thus, top feed roll 11 is considerably set back orrearwardly with respect to bottom feed roll 11a, and the nip 20 betweeneach roller a, b of top feed roll 11 and bottom feed roll 11a is locatedrearwardly of the axis of bottom feed roll 11a with respect to thedirection of movement of strands 14, 15 through the drafting unit.

Consequently, each strand 14, 15 is fed into the corresponding breakerdrafting zone A by being directed upwardly and forwardly through therespective nip 29, and a break draft is imparted to the strand in itscourse to nip 21 while each strand is partially looped over andpartially around bottom feed roll 11a. The relative positions of feedrolls 11, 11a, apron supporting rolls 12, 12a and the aprons 12, 12cthereover are such that, although the angle between nip and thepoint oftangency of bottom feed roll 11a may be as low as 85, each strand islooped in moving engagement with the upper surface of the bottom feedroll through an arc in the range of about 90 to 110 from and forwardlyof nip 20 as the strand passes out of engagement with roll 11a at apoint forwardly of the point of tangency of bottom feed roll 11a and tonip 21.

It is preferred that the arc of contact of each strand 14, 15 withbottom feed roll 11a is about 100 with respect to the axis of bottomfeed roll 11a. Additionally, the relative positions of the draftingrolls are such that each strand passes through the main or secondarydrafting zone B in a different angular plane than that of each suchstrand between feed roll 11a and intermediate rolls 12, 12a. Therelationship of such relatively different planes of the passage of eachstrand and the diameters and relative positions of rolls 11a, 120 aresuch that each strand also is partially looped around the respective topdraft apron 12b between a point rearwardly of the point of tangency ofapron 12b and the nip 21 through an arc of no more than about 25 andpreferably in the range of about 18 to 25.

The total length of the actual path of each strand l4, 15 between thehips 20, 21 is longer than the longest fibers in the strands while theunguided length of the path of the strand between the bottom feed roll11a and top apron 12b is no greater than the average staple length ofthe fibers being drafted.

Although aprons 12b, 120 are preferred, it is to be understood that theymay be omitted, if desired, in which instance all of the top rolls 11-l3may be cushion rolls all having the same diameter of cots a, b thereon,and the bosses of all of the bottom rolls 11a, 12a, 13a then should beof the same diameter with respect to each other. Such bosses usually arefluted as shown in FIG. 3.

As is conventional, bottom delivery roll 13a is supported for rotationin suitable bearings carried by the front portions of a plurality ofspaced roll stands 25,

only one of which is shown in FIG. 1. Also, bottom feed roll 11a andintermediate bottom roll 12a are mounted in suitable bearings positionedin slide blocks 26 carried by the roll stands 25. The bottom draftingrolls Ila-13a are driven by suitable connections to a drive means 27(FlG. 3) to, in turn, drive the rollers a, b of top drafting rolls,11-13 through the strands 14, 15 passing therebetween so as to impartthe desired draft to the textile strands, as is well known.

Any suitable loading or pressure means may be provided for maintainingtop drafting rolls Ila-13a in the desired spaced relationship and forapplying the desired load or yielding downward pressure thereto. By wayof example, a loading device 30 is provided which is of a type such asis disclosed in my said copending application, Serial No. 153,615.

Briefly, loading device 30 comprises a releasable loading arm orweighting arm 31 pivotally mounted on a bracket 31 carried by a fixedframe member 32 spaced rearwardly of the drafting rolls 1 1-13, 1la-l3a. A suitable spring 34, acting through linkage 35 and a releasinglever 36, imparts downward pressure to the forward portion of weightingarm 31, which forward portion overlies the medial portion of the rollerneck shafts c of top drafting rolls 11-13.

The forward portion of weighting arm 31 has a plurality of invertedsubstantially U-shaped top roll holders or carriers 40 projectingdownwardly therefrom and adjustably mounted thereon, there being one ofthe top roller holders 40 for each of the top rolls 11-13. The top rollholders 40 are relatively narrow and each of them receives and engages arelatively small medial portion of each respective roller neck shaft 0,thus transmitting downward pressure from loading or weighting arm 31 torelatively narrow medial portions of the roller neck shafts c of toprolls 11-13 so that the rollers a, b of top feed roll 11 and topdelivery roll 13 press the respective strands 14, 15 against therespective bottom rolls 11a, 13a and so that the top aprons 12b pressthe textile strands 14, 15 against the respective bottom aprons 12cunder predetermined pressures during operation of the drafting units.Since the drafting units and loading device 30 are disclosed in saidcopending application, a further description thereof is deemedunnecessary.

Since the nips between the top feed roller pair a, b and bottom feedroll 11a are located rearwardly of the axis of bottom feed roll 11a withrespect to the direc tion of travel of the textile strands 14, 15through the drafting unit, it follows that the axis of top feed roll 11is spaced a considerable distance rearwardly of the axis of bottom feedroll 11a. Consequently, the force of the downward pressure acting ononly a relatively narrow medial portion of the roller neck shaft c oftop feed roll 11, the differing tensile forces of the textile strands14, 15 acting on the top feed roller pair a, b the spacing between thelatter rollers and the spacing between the adjacent textile strands 14,15 are factors which separately and collectively tend to tilt the topfeed roll 11 in a direction transversely of the direction of the pathsof travel of the textile strands 14, 15 through the drafting units andabout the point at which the pressure is being applied to the top feedroller neck shaft c.

It should be noted that, if top feed roll 1 1 is permitted to tiltexcessively, the axis of top feed roll 11 will be inclined relative tothe axis of bottom feed roll 11a and thereby cause variation in thedistance between the nips at the top feed roller pair a, b and the nips21 at the respective pairs of draft aprons 12b, 12c. Also, this may varythe effective widths of the two nips 20 such that each strand l4, 15might not be equally restrained across its entire width by the top andbottom feed rolls 11, 11a and repeated variations in the position of thetop feed roll 11, as caused by tilting the same, will increase thetemperature of the rollers a, b thereof, cause the latter rollers a, bto become damaged or worn excessively in less than their normal usefullife, and reduce the quality of the textile strands l4, 15 beingdrafted.

According to the invention, however, an idler supporting roll 45preferably of substantially lesser diameter than either of the feedrolls 11, 11a, is positioned beneath and in nipping relation with topfeed roll 11, and is rotatable solely by top feed roll 11 and thestrands passing therebetween so as to prevent top feed roll 11 fromtilting excessively relative to bottom feed roll 11a under the force ofthe loading device 30. The idler supporting roll 45 preferably has asmooth peripheral surface and is loosely or freely rotatably mounted insuitable bearings 46, preferably roller bearings, mounted in the slideblocks 26 carried by the roll stands (FIG. 1).

It is preferred that the supporting roll 45 is relatively short and,accordingly, it may be made of a length about equal to the distancebetween the centers of adjacent roll stands 25 so that the top feed roll11 need overcome relatively little inertial force in order to transmitrotation to the corresponding idler supporting roll 45. It is to benoted that idler supporting roll 45 forms an additional pair of nipswith the two rollers a, b of top feed roll 11 with such additional pairof nips as illustrated in FIG. 2, being about 90 from the nips definedby the feed rolls 11, 20, with respect to the axis of top feed roll 11,so as to cause the textile strands to arcuately engage about one quarterof the surface of top feed roll 11. To facilitate guiding the strands14, 15 into the respective additional pair of nips and the threading ofthe strands therethrough and upwardly through the feed roll nips 20, thetrumpets or strand guide members 16, 17 are positioned rearwardly of andclosely adjacent the respective pair of additional nips and the openingsor passages through strand guide members l6, 17 are substantiallytangentially aligned with the proximal portions of idler roll 45 and thetop feed roller pair a, b forming the additional pair of nips.

it is thus seen that the supporting roll 45 supports the rearwardlyoffset top feed roll 11 by its nipping relation with the top feed rollerpair a, b thereof in the adjacent pair of side-by-side drafting unitsthereby providing stabilizing means preventing the top feed roll frombeing tilted excessively about the relatively narrow medial portion ofthe respective roller neck shaft c being enga'ged by the respective toproll holder 40 of the loading or pressure means 30. Thus, the tilting ofthe top feed roll relative to bottom feed roll 11a as by differingtensile forces of the strands l4, l5 acting on the top feed roller paira, b, is eliminated except for slight fluctuations of the top feedroller pair which may be effected by variations in mass and/or densityof the strands l4, 15 being fed to the next succeeding set of draftingrolls [2, 12a and the aprons 12b, 12c thereon. Also, it is to be notedthat the idler supporting roll 45 facilitates positioning the trumpetsor guide members l6, 17 so that an operator may easily thread thestrands through the guide members 16, 17 to the feed rolls 11, 11a in adirection generally parallel to the mean path of travel of the strandsthrough the drafting units.

in the drawings and specification, there has been set forth a preferredembodiment of the invention and, although speeific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

That which is claimed is:

1. A textile drafting system comprising a pair of sideby-side draftingunits for drafting respective spacedapart textile strands therethrough,a series of sets of drafting rolls common to both drafting units andincluding a set of top and bottom feed rolls, a set of top and bottomintermediate rolls and a set of top and bottom delivery rolls, the toproll of each set comprising a roller neck shaft having a pair of axiallyspaced rollers thereon forming a respective pair of nips with thecorresponding bottom roll through which the respective strands passduring drafting thereof, said bottom feed roll being offset upwardly byabout one-half of its diameter with respect to a substantially commonplane through the axes of said bottom intermediate roll and said bottomdelivery roll, said top feed roll being offset rearwardly of said bottomfeed roll whereby the nips of the bottom feed roll and the pair ofrollers of said top feed roll are offset rearwardly of the axis of saidbottom feed roll, pressure means engaging relatively narrow medialportions of said roller neck shafts between the respective pairs ofrollers and applying a downward force thereto, stabilizing meanspreventing excessive tilting of said rearwardly offset top feed rollabout the engaged medial portion of the roller neck shaft thereof bydiffering tensile forces of the strands acting on the respective rollersof said top feed roll during drafting, said stabilizing means includingan idler roller positioned beneath said top feed roll and forming anadditional pair of nips with the respective rollers thereof, said idlerroll being so positioned relative to said top feed roll that theadditional pair of nips formed therewith cause the textile strands intheir path of travel to said first recited nips to arcuately engageabout one quarter of the surface of the top feed roll, means supportingsaid idler roll for free rotation by the rollers of said top feed roll,and means guiding the strands into the respective additional pair ofnips to facilitate threading the strands therethrough and upwardlythrough the nips of said feed rolls.

2. A drafting system according to claim 1, wherein said pressure meansis provided with inverted substantially U-shaped holders thereonengaging the respective roller neck shafts at points about halfwaybetween the respective pairs of said rollers.

3. A drafting system according to claim 2, wherein said idler supportingroll is of substantially less diameter than said feed rolls and has asubstantially smooth peripheral surface engaging said strands.

4. A drafting system according to claim 3, wherein said strand guidingmeans includes a pair of guide members positioned rearwardly of andclosely adjacent said additional pair of nips and having openingstherethrough for guiding the respective strands into said additionalpair of nips.

5. A drafting system according to claim 4, wherein the openings in saidguide members are positioned in substantially tangential alignment withthe proximal portions of the peripheral surfaces of said rollers of saidtop feed roll and said idler roll forming said additional pair of nips.

1. A textile drafting system comprising a pair of side-by-side draftingunits for drafting respective spaced-apart textile strands therethrough,a series of sets of drafting rolls common to both drafting units andincluding a set of top and bottom feed rolls, a set of top and bottomintermediate rolls and a set of top and bottom delivery rolls, the toproll of each set comprising a roller neck shaft having a pair of axiallyspaced rollers thereon forming a respective pair of nips with thecorresponding bottom roll through which the respective strands passduring drafting thereof, said bottom feed roll being offset upwardly byabout one-half of its diameter with respect to a substantially commonplane through the axes of said bottom intermediate roll and said bottomdelivery roll, said top feed roll being offset rearwardly of said bottomfeed roll whereby the nips of the bottom feed roll and the pair ofrollers of said top feed roll are offset rearwardly of the axis of saidbottom feed roll, pressure means engaging relatively narrow medialportions of said roller neck shafts between the respective pairs ofrollers and applying a downward force thereto, stabilizing meanspreventing excessive tilting of said rearwardly offset top feed rollabout the engaged medial portion of the roller neck shaft thereof bydiffering tensile forces of the strands acting on the respective rollersof said top feed roll during drafting, said stabilizing means includingan idler roller positioned beneath said top feed roll and forming anadditional pair of nips with the respective rollers thereof, said idlerroll being so positioned relative to said top feed roll that theadditional pair of nips formed therewith cause the textile strands intheir path of travel to said first recited nips to arcuately engageabout one quarter of the surface of the top feed roll, means supportingsaid idler roll for free rotation by the rollers of said top feed roll,and means guiding the strands into the respective additional pair ofnips to facilitate threading the strands therethrough and upwardlythrough the nips of said feed rolls.
 2. A drafting system according toclaim 1, wherein said pressure means is provided with invertedsubstantially U-shaped holders thereon engaging the respective rollerneck shafts at points about halfway between the respective pairs of saidrollers.
 3. A drafting system according to claim 2, wherein said idlersupporting roll is of substantially less diameter than said feed rollsand has a substantially smooth peripheral surface engaging said strands.4. A drafting system according to claim 3, wherein said strand guidingmeans includes a pair of guide members positioned rearwardly of andclosely adjacent said additional pair of nips and having openingstherethrough for guiding the respective strands into said additionalpair of nips.
 5. A drafting system according to claim 4, wherein theopenings in said guide members are positioned in substantiallytangential alignment with the proximal portions of the peripheralsurfaces of said rollers of said top feed roll and said idler rollforming said additional pair of nips.